GMC Repair: transmission, gmc 4x4, jegs

Question
I have a 1979 gmc 4x4 in drive and overdrive the truck wont go past 3okm it just starts to over rev and has no power. but if i start from first gear then shift to 2nd i can get to 60km before it over revs this is a automatic transmission is the drive and overdrive on its way out, should the tranny be re-built, the fluid is up and does not smell burnt

Answer
It sounds like you will need to have it rebuilt. I had a 1983 c-10 that went through a similar thing. Here in Oklahoma City it was around 700.00-1500.00. You can try some Lucas and manually shift it. However, it sounds like you are at the point of rebuild. You may look at jegs and see if they may have one with a little more power range for about the same price.